In a home, business, or other setting having a doorbell with a main or primary chime unit, it can be desirable to have a second chime in a remote location of the building, such as the basement for example. Because the remote chime is often installed after the original doorbell is installed, it is usually easier to use a wireless radio frequency (RF) transmitter to transmit an ‘on’ signal from the main doorbell actuation circuit to the remote chime than to install wiring connecting the remote chime to the doorbell actuation circuit.
Remote chimes activated by an RF transmitter connected to the primary doorbell circuit are known. For example, U.S. Pat. Nos. 4,523,193 and 6,414,589 both disclose a remote doorbell chime including an RF transmitter connected to the main doorbell wiring and a corresponding receiver connected to the remote chime. The '193 patent includes a full wave rectifier connected across the primary doorbell AC circuit outputting DC to a transmitter circuit including a transmitter, a filter capacitor, and a zener diode. The '589 patent includes parallel switches for simultaneously completing a primary doorbell circuit and an RF transmitter circuit in parallel. It would be desirable, therefore, to have a switching mechanism for activating an RF transmitter to activate a remote chime unit simultaneously with the primary chime unit which does not draw current away from the primary chime unit during remote chime use.